Spark-plug.



A. SCHMIDT. smnx rmm. LPPLIOLTIOI FILED JUIE 9, 1910.

Patented Jam 3, 1911.

. the

' UNITED STATES PATENT ornion.

ALBERT SCHMIDT, OF FLINT, MICHIGAN, ASBIGNOB '10 CHAMPION IGNITION COl- PANY, OF FLINT, MICHIGAN, A CORPORATION 01 MICHIGAN.

SPARK-PLUG.

Specification of Letters Patent.

" Patented Jan. 3, 1911.

To all whom it may concern:

Be it known that I ALBERT SCHMIDT, acitizen of the United states of America, residing at Flint, in the count of Genesee and State of Michi an, have invented certain new and usefu Improvements in Spark- Plugs, of which the followin is a'specification, reference being had t erein to the accompanying drawings.

This invention relates to improvements in spark plugs and its object is to provide a suitable su ort for the insulating member thereof whicli will ermit of the free ex ansion of the parts and prevent breakage o the porcelain insulation, at the same time securel holding said porcelain insulating mem r and making a tight joint to prevent products of combustion from escaping.

To this end the invention conslsts in the construction, arrangement and combination of arts all as hereinafter more fully described and particularly pointed out in the claims reference being had to the accompanying drawing, in which,

F lgure 1 is a vertical section through a device embodying the invention and showing the insulating plug in elevation; Fi 2 is a transverse section on the line ww 0 Fig. 1; Fig. 3 is a similar section on the line y-y of Fig. 1; and Fig. 4 is a perspective detail of a supporting thimble.

As shown in the drawing 1 is a metal bushing or shell rovided with a tapering screwthreaded en and a hexagonal portion or head by means of which the bushing may be screwed into a screwthreaded o enmg in an engine cylinder. This bushing is formed with a bore 2 in its inner end and an enlarged bore or chamber 3 in its outer end, the extreme outer end of the chamber being further enlarged to form a shoulder or ledge 4 and is internally screwthreaded to receive a screwthreaded ring nut 5. A orcelain insulating plug ,6 is supported within the bushing with its inner re need and tapered end 7 extending within the bore 2 of the bushing and its outer cylindrical end extending outward throu h the nut 5. Within the lower end of the c amber 3 the plug 6 is formed with an enlarged rounded ortion or bead 8 and an axial hole is provided in pllufg for a rod 9, the inner end 10 of whic orms one electrode. The other electrode of the device is formed by a wire 11 in firmly, clamps the rin secured to the inner end of the bushin and bent laterally over and adjacent to the mner end of the rod. The rod 9 is secured within the plug in any desired manner as by a nut 12 on its screwthreaded outer end.

The insulating plug 6 is supported within the bushing with a space between it. and the bushin by means of a thimble 13 which is provide at its upper end with a thickened rim portion or ring 14 formed integral therewith and the body portion of the thimble extends downward from the rin and v is contracted or inwardly tapere toward its lower end. This body portion of the thimble is of'thin metal so that it may be forced upon the insulating plug with the extreme lower end of the body en a in the enlarged portion or bead 8 of sai ing. The thin metal of the body is then s un or otherwise formed down upon the bea to embrace the same, and firmly engage the thimble with the plug. Preferabl the bead, in the manufacture of the porce ainis left a rough so that the bead may e plated with a deposit of copper orother suitable metal which will enter the pores of the porcelain and firmly adhere thereto. To this plated bead, the portion of the thimble which is formed down thereon may be secured by brazin or the like to firmly secure the lower end of the thimble to the plug and form a tight joint between, which will prevent the products of combustion from blowing through between the parts when the device is in use. The ring 14, when the plug is in place within the bushing engages the shoulder or ledge 4 and the ring nut 5 engages the upper side of the ring 14 and when screwed 14 of the thimble securel between said le ge and nut. The insulatlng plug is thus suspended by the thimble within the chamber of the bushing and the thimble-extending across the space between the plug and the walls of the chamand wal of the chamber, permits a free expansion and contraction of the parts without danger of putting such a strain upon the porcelain as to crack the same and render" it useless.

Having thus fully described my invention what I claim is 1. A device of the character described comprising an insulating member, a member within which said insulating member is supported with a space between, and a member spanning said space and rigidly secured at its inner portion to said insulating member and at its outer portion to said supporting member, said spanning member being adapted to yield between its inner and outer portions.

2. A device of the character described comprising an insulating member, an outer member surrounding the insulating member, and a tubular supporting member secured at one end to the insulating member to support and hold the same and secured at its opposite end to the outer member, said supporting member being adapted to yield intermediate its ends.

3. A device of the character described comprising an insulating member, an outer member surrounding the insulating member with a space between, a tapering tubular supporting member rigidly secured at its smaller end to the insulating member, and forming a tight joint therewith and detachably and rigidly attached at its larger end to the outer member, said member extending across the space between the insulating member and the outer member to close said space and free to yield laterally intermediate its ends.

LA device of the character described comprising a bushing formed with a chamber havin an inwardly projecting ledge, an insulating member in said chamber with a space between it and the wall of said chamber, a supporting member rigidly se- E cured at its inner portion upon the insulatl ving member, and extending outward into engagement with said ledge, said supporting member forming a wall extending across said space to close the same and free to yield laterally, and a ring nut within the outer end of the chamber to clamp the outer portion of said supporting member between said nut and ledge.

5. A device of the character described comprising a bushing having a chamber, an insulating member supported within said chamber with a space'between it and the wall of the chamber and havin an annular bead, a supporting member em racing said bead to rigidly secure the supporting memher to the insulating member and having a yielding portion extending outward across said space, and means for detachably and rigidly securing the outer portion of the supportin member to the bushing to form a tight joint therewith.

6. A device of the character described comprising a bushing, an insulating plu formed with an annular bead and supporte' within the bushing with a space between the plug and bushing, a tapered tubular supporting member sleeved upon the plug, and having its smaller end formed down upon said bead into en agement with the upper and lower sides of said bead to prevent the movement of said member upon the plug and .toyforma tight joint, and means engaging the' larger end of the supporting member to rigidl and detachably secure said member to t e bushin In testimony whereof I a 1X my signature in presence of two witnesses.

, ALBERT SCHMIDT.

Witnesses:

B. DE GUICHARD,

ALICE Swnnrwoon. 

